2FWQ:
reference: Structural evidence for an enolate intermediate in GFP fluorophore biosynthesis., Barondeau DP, Tainer JA, Getzoff ED, J Am Chem Soc. 2006 Mar 15;128(10):3166-8. PMID: 16522096

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).